The present invention relates generally to a modulation device which causes a mobile tracking device to not approach closer to an asset, and more particularly, to a modulation device which directs the mobile tracking device away from the asset or disables the tracking device.
Presently, a multitude of mobile tracking devices are known which identify an asset and attempt to move closer to the asset and potentially contact the asset. Examples of mobile tracking devices include infrared based mobile tracking devices which examine the infrared energy which is emitted by the asset and detected by the mobile tracking device. These infrared mobile tracking devices alter their direction of travel to track the highest infrared energy being detected within their field of view. Such mobile tracking devices may rely on a non-imaging detection system or an imaging detection system.
There are several devices available to misdirect a mobile infrared tracking device away from an asset. One exemplary device is infrared hot bodies which appear brighter to the mobile infrared tracking device than the asset. These infrared hot bodies may be expelled by the asset. The mobile tracking device detects the brighter infrared hot bodies and follows the hot bodies as they become further spaced apart from the asset; thereby directing the mobile infrared tracking device away from the asset. Exemplary infrared hot bodies include flares.
Another type of device is a laser device which directs a pulsed or modulated laser signal at a detection system of the mobile tracking device. The pulsed or modulated laser signal is tailored to the specific characteristics of the mobile tracking device. An example of one device which is tailored to multiple types of tracking devices is disclosed in U.S. Pat. No. 6,359,710.